Haptic devices using electroactive polymers

ABSTRACT

Haptic feedback device and method for using an electroactive polymer (EAP) actuator to provide haptic feedback force sensation to a user. The device includes a sensor that detects the a user&#39;s touch on a touch surface and an electroactive polymer actuator responsive to input signals from the sensor outputs a haptic feedback force to the user caused by motion of the actuator.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application which claims the benefit of U.S.patent application Ser. No. 09/866,385, filed May 24, 2001 now U.S. Pat.No. 7,196,688 by Bruce M. Schena, entitled, “Haptic Devices UsingElectroactive Polymers”, which claims the benefit of U.S. ProvisionalPatent Application No. 60/206,929, filed May 24, 2000 also by Bruce M.Schena, entitled, “Haptic Feedback Devices Using ElectroactivePolymers”.

BACKGROUND

The present invention relates generally to interface devices forallowing humans to interface with computer systems, and moreparticularly to low-cost computer interface devices that allow the userto provide input to computer systems and allow computer systems toprovide haptic feedback to the user.

A user can interact with an environment displayed by a computer toperform functions and tasks on the computer, such as playing a game,experiencing a simulation or virtual reality environment, using acomputer aided design system, operating a graphical user interface(GUI), navigate web pages, etc. Common human-computer interface devicesused for such interaction include a mouse, joystick, trackball, gamepad,steering wheel, stylus, tablet, pressure-sensitive sphere, or the like,that is connected to the computer system controlling the displayedenvironment. Typically, the computer updates the environment in responseto the user's manipulation of a physical manipulandum such as a joystickhandle or mouse. The computer senses the user's manipulation of the userobject through sensors on the interface device that send locativesignals to the computer. In other applications, interface devices suchas remote controls allow a user to interface with the functions of anelectronic device or appliance.

In some interface devices, force (kinesthetic) feedback and/or tactilefeedback is also provided to the user, more generally known collectivelyherein as “haptic feedback.” These types of interface devices canprovide physical sensations which are felt by the user manipulating auser manipulandum of the interface device, such as a joystick handle,mouse, wheel, etc. One or more motors or other actuators are coupled tothe manipulandum and are connected to the controlling computer system.The computer controls forces on the manipulandum and/or device housingin conjunction and coordinated with displayed events and interactions bysending control signals or commands to the actuators. The computersystem can thus convey physical force sensations to the user inconjunction with other supplied feedback as the user is grasping orcontacting the interface device or manipulatable object of the interfacedevice.

One problem with current haptic feedback controllers in the homeconsumer market is the high manufacturing cost of such devices, whichmakes the devices expensive for the consumer. A large part of thismanufacturing expense is due to the inclusion of complex and multipleactuators and corresponding control electronics in the haptic feedbackdevice. In addition, high quality mechanical and force transmissioncomponents such as linkages and bearings further add to the cost of thedevice. Some low cost haptic devices exist, but are highly limited intheir ability to output haptic sensations.

A need therefore exists for a haptic feedback device that is lower incost to manufacture yet offers the user compelling haptic feedback toenhance the interaction with computer applications.

SUMMARY

The present invention is directed toward providing haptic feedback in aninterface device using electroactive polymer (EAP) actuators, which canprovide haptic sensations more efficiently and at lower cost than manyexisting technologies for haptic devices.

More particularly, a haptic feedback interface device of the presentinvention is in communication with a host computer implementing a hostapplication program and is manipulated by a user. The interface deviceincludes a sensor device that detects the manipulation of the interfacedevice by the user and outputs sensor signals representative of themanipulation, and an electroactive polymer actuator responsive to inputsignals and operative to output a force to the user caused by motion ofthe actuator. The output force provides a haptic sensation to the user.The interface device may also include a device housing that isphysically contacted by the user. In some embodiments, the force andhaptic sensation can be correlated with an event or interactionimplemented by the host computer.

Various embodiments of interface devices employing EAP actuators aredescribed. The force output by the electroactive polymer actuator can bean inertial force that is caused by moving an inertial mass. The forceoutput by the electroactive polymer actuator can be a rotary force, alinear force, or a force caused by bending of the EAP element or areaexpansion of the EAP element. The electroactive polymer actuator canmove a button on the interface device to output the force to the user,or the actuator can move one or more portions of the device housing. TheEAP actuator can also move an element acting as a brake shoe against amoving part of the interface device to cause a resistance to the movingpart, such as an axle for a wheel, a medical tool, a disc, or otherpart. The EAP actuator can provide haptic sensations for a rotatingwheel on said interface device, a trackpoint controller, a rotatingknob, a rotating sphere, a stylus, or other manipulandums. One or more(e.g. an array) electroactive polymer actuators can also be used to movemembers directly into contact or in shear with skin of the user toprovide tactile sensations. A method similarly provides EAP actuators inhaptic sensation output.

In other aspects of the present invention, a haptic feedback interfacedevice in communication with a host computer includes a device housingthat is physically contacted by said user and an electroactive polymer(EAP) element that is able to detect a manipulation of a manipulandum ofthe interface device by the user and output sensor signalsrepresentative of the manipulation, as well as output a force to theuser in response to an input signal, the force caused on motion of theEAP element and providing a haptic sensation to the user. The EAPelement can detect contact of the user with the manipulandum, or detectan amount of pressure on the EAP element caused by the user.

The present invention advantageously provides tactile feedbacksensations for a tactile feedback device using electroactive polymeractuators. These actuators have several advantages, including highenergy density, rapid response time, customizability in shape andperformance characteristics, compactness, easy controllability, lowpower consumption, high force output and deflections/amount of motion,natural stiffness, sensing and actuation functions, relatively low rawmaterials cost, and relatively inexpensive manufacturing cost, makingthem desirable for haptic feedback and sensing devices.

These and other advantages of the present invention will become apparentto those skilled in the art upon a reading of the followingspecification of the invention and a study of the several figures of thedrawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a haptic feedback system suitablefor use with the present invention;

FIG. 2 a is a side elevational view of an electroactive polymer elementin a bending motion;

FIG. 2 b is a top plan view of an electroactive polymer element in abending motion;

FIG. 2 c is a side elevational view of an electroactive polymer sandwichstructure providing linear and bending motion;

FIG. 2 d is a perspective view of an electroactive polymer element in acylindrical configuration to provide motion in multiple degrees offreedom;

FIG. 2 e is a perspective view of an electroactive polymer structurethat provides an area expansion of the element;

FIG. 2 f is a perspective view of an electroactive polymer structure ina cylindrical structure that provides axial motion of the element;

FIG. 3 is a perspective view of an example mouse interface devicesuitable for use with EAP actuators of the present invention;

FIG. 3 a is a side elevational view of a mouse embodiment in which abutton is moved in its degree of freedom by an electroactive polymeractuator;

FIG. 3 b is a top plan view of a mouse embodiment in which a button ismoved laterally by an electroactive polymer actuator;

FIG. 3 c is a top plan view of a mouse embodiment in which a buttonincludes an array of multiple electroactive polymer actuators;

FIG. 4 a is a schematic view of an embodiment in which an inertial massis moved linearly by an electroactive polymer actuator to provideinertial sensations;

FIG. 4 b is a schematic view of an embodiment in which an inertial massis moved rotationally by an electroactive polymer actuator to provideinertial sensations;

FIG. 4 c is a view of an embodiment in which multiple inertial massesare moved by an electroactive polymer actuators;

FIG. 5 a is a side view of a mouse embodiment in which a entire coverportion of the mouse is moved by an electroactive polymer actuator toprovide tactile sensations;

FIG. 5 b is a top plan view of a mouse embodiment in which side portionsof the mouse are moved by an electroactive polymer actuator to providetactile sensations;

FIG. 5 c is a top plan view of a mouse embodiment in which top portionsof the mouse are moved by an electroactive polymer actuator to providetactile sensations;

FIG. 5 d is a side view of a mouse embodiment in which a rear topportion of the mouse is moved by an electroactive polymer actuator toprovide tactile sensations;

FIG. 6 is a top view of an embodiment in which a sphere is braked by anelectroactive polymer actuator;

FIG. 7 a is a side view of a wheel embodiment in which a rotatable wheelincludes an inertial mass that is rotationally moved by an electroactivepolymer actuator;

FIGS. 7 b and 7 c illustrate a wheel embodiment including a number ofelectroactive polymer actuators which expand in area;

FIG. 7 d is a perspective view of a wheel embodiment in which arotatable wheel is braked by an electroactive polymer actuator;

FIG. 7 e is a side elevational view of a wheel embodiment in which theentire rotatable wheel is moved laterally and vertically byelectroactive polymer actuators;

FIG. 8 a is a perspective view of a trackpoint controller in which anelectroactive polymer actuator provides haptic feedback in its degreesof freedom;

FIGS. 8 b and 8 c is perspective and side sectional views of atrackpoint controller in which an electroactive polymer actuatorprovides haptic feedback by linearly moving a poker against the user;

FIG. 8 d is a perspective view of a trackpoint controller in whichelectroactive polymer actuators provide haptic feedback in lineardegrees of freedom;

FIG. 9 a is a perspective view of a vertical pin moved linearly by anelectroactive polymer actuator against a user's finger;

FIGS. 9 b and 9 c are perspective views of arrays of the vertical pinsof FIG. 9 a;

FIGS. 9 d and 9 e are side views of a vertical pin moved laterally by anelectroactive polymer actuator against a user's finger;

FIG. 10 is a side elevational view of a device in which an electroactivepolymer actuator provides braking forces on a medical tool;

FIG. 11 is a side elevational view of a device in which an electroactivepolymer actuator provides forces to a trigger on an interface device;

FIG. 12 a is a front view of a knob in which an electroactive polymeractuator provides direct rotary forces in the rotary degree of freedomof the knob;

FIG. 12 b is a perspective view of a knob in which an electroactivepolymer actuator provides braking forces in the rotary degree of freedomof the knob;

FIG. 13 is a side view of a rotating disc in which an electroactivepolymer actuator provides braking forces in the rotary degree of freedomof the disc;

FIG. 14 a is a side elevational view of a stylus in which anelectroactive polymer actuator provides linear forces to the tip of thestylus;

FIG. 14 b is a side elevational view of a stylus in which anelectroactive polymer actuator provides linear forces to the front endof the stylus;

FIG. 14 c is a side elevational view of a stylus in which anelectroactive polymer actuator provides forces to a button on thestylus;

FIGS. 14 d and 14 e are side elevational and perspective views of astylus in which electroactive polymer actuators provide outward forcesfrom the stylus body;

FIG. 15 a is a front view of a steering wheel in which an electroactivepolymer actuator provides inertial forces;

FIG. 15 b is a side view of a joystick handle in which an electroactivepolymer actuator provides inertial forces;

FIGS. 15 c and 15 d are perspective and side elevational views of ajoystick handle in which electroactive polymer actuators provide brakingforces in the degrees of freedom of the joystick handle;

FIG. 16 is a perspective view of a rotating cylinder controller in whichelectroactive polymer actuators provide braking forces in the degrees offreedom of the cylinder;

FIG. 17 a is a side elevational view of a tactile element in whichelectroactive polymer actuators provide linear motion to the element;and

FIG. 17 b is a side elevational view of a tactile element in whichelectroactive polymer actuators provide lateral, shear motion to theelement.

DETAILED DESCRIPTION

FIG. 1 is a block diagram illustrating a haptic feedback system suitablefor use with any of the described embodiments of the present invention.The haptic feedback system includes a host computer system 14 andinterface device 12.

Host computer system 14 preferably includes a host microprocessor 100, aclock 102, a display screen 26, and an audio output device 104. The hostcomputer also includes other well known components, such as randomaccess memory (RAM), read-only memory (ROM), and input/output (I/O)electronics (not shown).

Host computer 14 can be a personal computer or workstation and mayoperate under any well-known operating system. Alternatively, hostcomputer system 14 can be one of a variety of home video game consolesystems commonly connected to a television set or other display, such assystems available from Nintendo, Sega, Sony, or Microsoft. In otherembodiments, host computer system 14 can be a “set top box” which can beused, for example, to provide interactive television functions to users,or a “network-” or “internet-computer” which allows users to interactwith a local or global network using standard connections and protocolssuch as used for the Internet and World Wide Web. In otherimplementations, the host computer can be an appliance or electronicdevice, vehicle computer, etc.

Host computer 14 preferably implements a host application program withwhich a user is interacting via interface device 12 which includeshaptic feedback functionality. For example, the host application programcan be a video game, word processor or spreadsheet, Web page or browserthat implements HTML or VRML instructions, scientific analysis program,virtual reality training program or application, or other applicationprogram that utilizes input of mouse 12 and outputs force feedbackcommands to the device 12. Herein, for simplicity, operating systemssuch as Windows™, MS-DOS, MacOS, Linux, Be, etc. are also referred to as“application programs.” Herein, computer 14 may be referred as providinga “graphical environment,”, which can be a graphical user interface,game, simulation, or other visual environment. The computer displays“graphical objects” or “computer objects,” which are not physicalobjects, but are logical software unit collections of data and/orprocedures that may be displayed as images by computer 14 on displayscreen 26, as is well known to those skilled in the art. Suitablesoftware drivers which interface such software with computerinput/output (I/O) devices are available from Immersion Corporation ofSan Jose, Calif.

Display device 26 can be included in host computer 14 and can be astandard display screen (LCD, CRT, flat panel, etc.), 3-D goggles, orany other visual output device. Typically, the host application providesimages to be displayed on display device 26 and/or other feedback, suchas auditory signals. Audio output device 104, such as speakers, ispreferably coupled to host microprocessor 100 via amplifiers, filters,and other circuitry well known to those skilled in the art and providessound output to user when an “audio event” occurs during theimplementation of the host application program. Other types ofperipherals can also be coupled to host processor 100, such as storagedevices (hard disk drive, CD ROM drive, floppy disk drive, etc.),printers, and other input and output devices.

Interface device 12 is coupled to the computer 14 by a bus 20, whichcommunicates signals between device 12 and computer 14 and may also, insome embodiments, provide power to the device 12. In other embodiments,signals can be sent between device 12 and computer 14 by wirelesstransmission/reception. In some embodiments, the power for the actuatorcan be supplemented or solely supplied by a power storage deviceprovided on the device, such as a capacitor or one or more batteries.The bus 20 is preferably bi-directional to send signals in eitherdirection between host 14 and device 12. Bus 20 can be a serialinterface bus, such as an RS232 serial interface, RS-422, UniversalSerial Bus (USB), MIDI, or other protocols well known to those skilledin the art; or a parallel bus or wireless link.

Device 12 can include a local microprocessor 110. Local microprocessor110 can optionally be included within the housing of device 12 to allowefficient communication with other components of the device. Processor110 is considered local to device 12, where “local” herein refers toprocessor 110 being a separate microprocessor from any processors inhost computer system 14. “Local” also preferably refers to processor 110being dedicated to haptic feedback and sensor I/O of device 12.Microprocessor 110 can be provided with software instructions (e.g.,firmware) to wait for commands or requests from computer host 14, decodethe command or request, and handle/control input and output signalsaccording to the command or request. In addition, processor 110 canoperate independently of host computer 14 by reading sensor signals andcalculating appropriate forces from those sensor signals, time signals,and stored or relayed instructions selected in accordance with a hostcommand. Suitable microprocessors for use as local microprocessor 110include lower-end microprocessors as well as more sophisticated forcefeedback processors such as the Immersion Touchsense Processor.Microprocessor 110 can include one microprocessor chip, multipleprocessors and/or co-processor chips, and/or digital signal processor(DSP) capability.

Microprocessor 110 can receive signals from sensor 112 and providesignals to actuator 18 in accordance with instructions provided by hostcomputer 14 over bus 20. For example, in a local control embodiment,host computer 14 provides high level supervisory commands tomicroprocessor 110 over bus 20, and microprocessor 110 decodes thecommands and manages low level force control loops to sensors and theactuator in accordance with the high level commands and independently ofthe host computer 14. This operation is described in greater detail inU.S. Pat. Nos. 5,739,811 and 5,734,373, both incorporated herein byreference in their entirety. In the host control loop, force commandsare output from the host computer to microprocessor 110 and instruct themicroprocessor to output a force or force sensation having specifiedcharacteristics. The local microprocessor 110 reports data to the hostcomputer, such as locative data that describes the position of thedevice in one or more provided degrees of freedom. The data can alsodescribe the states of buttons, switches, etc. The host computer usesthe locative data to update executed programs. In the local controlloop, actuator signals are provided from the microprocessor 110 to anactuator 18 and sensor signals are provided from the sensor 112 andother input devices 118 to the microprocessor 110. Herein, the term“tactile sensation” refers to either a single force or a sequence offorces output by the actuator 18 which provide a sensation to the user.For example, vibrations, a single jolt, or a texture sensation are allconsidered tactile sensations. The microprocessor 110 can processinputted sensor signals to determine appropriate output actuator signalsby following stored instructions. The microprocessor may use sensorsignals in the local determination of forces to be output on the userobject, as well as reporting locative data derived from the sensorsignals to the host computer.

In yet other embodiments, other hardware can be provided locally todevice 12 to provide functionality similar to microprocessor 110. Forexample, a hardware state machine incorporating fixed logic can be usedto provide signals to the actuator 18 and receive sensor signals fromsensors 112, and to output tactile signals.

In a different, host-controlled embodiment, host computer 14 can providelow-level force commands over bus 20, which are directly transmitted tothe actuator 18 via microprocessor 110 or other circuitry. Host computer14 thus directly controls and processes all signals to and from thedevice 12, e.g. the host computer directly controls the forces output byactuator 18 and directly receives sensor signals from sensor 112 andinput devices 18. Other embodiments may employ a “hybrid” organizationwhere some types of forces (e.g. closed loop effects) are controlledpurely by the local microprocessor, while other types of effects (e.g.,open loop effects) may be controlled by the host.

Local memory 122, such as RAM and/or ROM, is preferably coupled tomicroprocessor 110 in device 12 to store instructions for microprocessor110 and store temporary and other data. In addition, a local clock 124can be coupled to the microprocessor 110 to provide timing data, similarto system clock 102 of host computer 14.

Sensors 112 sense the position or motion of the device (e.g. the housingor a manipulandum) in degrees of freedom and provides signals tomicroprocessor 110 (or host 14) including information representative ofthe position or motion. Sensors suitable for detecting motion includedigital optical encoders, other optical sensor systems, linear opticalencoders, potentiometers, optical sensors, velocity sensors,acceleration sensors, strain gauge, or other types of sensors can alsobe used, and either relative or absolute sensors can be used. Optionalsensor interface 114 can be used to convert sensor signals to signalsthat can be interpreted by the microprocessor 110 and/or host computersystem 14, as is well known to those skilled in the art.

Actuator(s) 18 transmits forces to the housing, manipulandum, buttons,or other portion of the device in response to signals received frommicroprocessor 110 and/or host computer 14. Device 12 preferablyincludes one or more actuators which are operative to produce forces onthe device 12 (or a component thereof) and haptic sensations to theuser. The actuator(s) are electroactive polymer (EAP) actuators, whichare described in greater detail below, and are “computer-controlled”,e.g., the force output from the actuators is ultimately controlled bysignals originating from a controller such as a microprocessor, ASIC,etc. Many types of additional actuators can be used in conjunction withthe electroactive polymer actuators described herein, including a rotaryDC motors, voice coil actuators, moving magnet actuators,pneumatic/hydraulic actuators, solenoids, speaker voice coils,piezoelectric actuators, passive actuators (brakes), etc. Actuatorinterface 116 can be optionally connected between actuator 18 andmicroprocessor 110 to convert signals from microprocessor 110 intosignals appropriate to drive actuator 18. Interface 116 can includepower amplifiers, switches, digital to analog controllers (DACs), analogto digital controllers (ADCs), and other components, as is well known tothose skilled in the art.

In some of the implementations herein, the actuator has the ability toapply short duration force sensation on the housing or manipulandum ofthe device, or via moving an inertial mass. This short duration forcesensation can be described as a “pulse.” The “pulse” can be directedsubstantially along a particular direction in some embodiments. In someembodiments, the magnitude of the “pulse” can be controlled; the senseof the “pulse” can be controlled, either positive or negative biased; a“periodic force sensation” can be applied, where the periodic sensationcan have a magnitude and a frequency, e.g. a sine wave; the periodicsensation can be selectable among a sine wave, square wave,saw-toothed-up wave, saw-toothed-down, and triangle wave; an envelopecan be applied to the period signal, allowing for variation in magnitudeover time. The wave forms can be “streamed” from the host to the device,as described in copending application Ser. No. 09/687,744, incorporatedherein by reference in its entirety, or can be conveyed through highlevel commands that include parameters such as magnitude, frequency, andduration.

Other input devices 118 can be included in device 12 and send inputsignals to microprocessor 110 or to host 14 when manipulated by theuser. Such input devices include buttons, dials, switches, scrollwheels, knobs, or other controls or mechanisms. Power supply 120 canoptionally be included in device 12 coupled to actuator interface 116and/or actuator 18 to provide electrical power to the actuator. or beprovided as a separate component. Alternatively, power can be drawn froma power supply separate from device 12, or power can be received acrossbus 20. Also, received power can be stored and regulated by device 12and thus used when needed to drive actuator 18 or used in asupplementary fashion.

The interface device 12 can be any of a variety of types; someembodiments are described further below. For example, the device 12 canbe a mouse device having planar degrees of freedom, in which the entirehousing is moved. Alternatively, a manipulandum on the device, such as ajoystick handle, a knob, a steering wheel, a trackball, etc., is movedby the user and tracked by sensors. Device 12 can also be a gamepad,joystick, steering wheel, stylus, touchpad, spherical controller, fingerpad, knob, track ball, or other device, some embodiments of which aredescribed below. Alternatively, a hand-held remote control device usedto select functions of a television, video cassette recorder, soundstereo, internet or network computer (e.g., Web-TV™) can be used withthe haptic feedback components described herein, or a cell phone,personal digital assistant, etc. The forces from the actuator(s) 18 canbe applied to the housing of the device 12, and/or a movablemanipulandum such as a joystick handle, steering wheel, knob, button,etc.

Electroactive Polymers in Haptic Feedback Devices

Electroactive polymers (EAP) are a class of polymers which can beformulated and/or processed to exhibit a wide range of physical,electrical, and electro-optical behaviors and properties.

When activated, such as by an applied voltage, EAP materials can undergosignificant physical movement or deformations, typically referred to aselectrostriction. These deformations can be along the length, width,thickness, radius, etc. of the material and in some cases can exceed 10%strain. Elastic strains of this magnitude are very unusual in commonmaterials and even more unusual in that they can be fully controlledwith the proper electronic systems. Materials in this class can be usedto do useful work in a compact, easy to control, low power, fast, andpotentially inexpensive package. They are often referred to as “electricmuscles” because of these properties. These deformation properties canbe used in the present invention to provide forces to a user in a hapticfeedback device.

Many of the materials can also act as high quality sensors, particularlyfor time-varying (i.e. AC) signals. When mechanically deformed (e.g. bybending, pulling, etc.), most EAP materials develop differentialvoltages which can be electrically measured. This ability to essentiallygenerate electric potential makes them promising as force, position,velocity, acceleration, pressure, etc. sensors in haptic feedbackdevices of the present invention. Many of these materials exhibitbi-directional behavior, and can act as either sensors or actuators, oract simultaneously as both sensors and actuators, depending on systemdesign.

At present, there are four main classes of EAP, each with variousadvantages, disadvantages, and issues. The four classes, all included inthe term “electroactive polymer” herein, are gels, ionic polymers (ionicpolymer metal composites or IPMC), conducting polymers, andelectrorestrictive polymers. Any of these types of EAP can be used inthe present invention, although some types may be more appropriate for aparticular application than other types. A variety of EAP structures aredescribed in the papers, “High-field electrostriction of elastomericpolymer dielectrics for actuator,” by Kornbluh et al.,“Electro-mechanics of iono-elastic beams as electrically-controllableartificial muscles,” by M. Shahinpoor, “Polymer Electrolyte Actuatorwith Gold Electrodes,” by K. Oguro et al., and “Microgripper designusing electro-active polymers,” by R. Lumia et al., all SPIE Conf. onElectroactive Polymer Actuators and Devices, SPIE Vol. 3669, 1999, allincorporated herein by reference.

In a majority of EAP materials, the actuation mechanism is based on themovement of ionic species either in or out of a polymer network.Currently, the most commercially viable of these is the electrostrictivepolymer class.

Electrorestrictive polymers presently can be classified in two classes:dielectric and phase transition. Dielectric polymers are typically asandwich construction of two electrically conductive (and compliant)electrodes with a dielectric polymer in between. At high electric fields(e.g., 100's to 1000's of volts), the attractive force of the electrodessqueezes the intervening dielectric such that significant motion(strain) is induced. In some cases, this strain can be greater than 50%.

Phase transition electrorestrictive materials also exhibit high strain(deformation) in the presence of electric fields, but the mechanism is aferroelectric-to-paraelectric transformation at the molecular chainlevel. One example of these materials has been developed by Q. M. Zhanget al. and is electron-irradiated polyvinelidenefluoride-trifluoroethylene (P(VDF-TrFE)) copolymer, described in thepaper, “Electromechanical Behavior of Electroactive P(VDF-TrFE)Copolymers”, SPIE Conf. on Electroactive Polymer Actuators and Devices,SPIE Vol. 3669, 1999, and incorporated herein by reference. Whenprocessed, P(VDF-TrFE) exhibits exceptional strain (>10% in some cases),extreme energy density (Joules/cm³), and high physical stiffness(elastic modulus). It is proposed that this class of materials exhibitsenergy densities exceeding that of traditional piezoceramics (PZT) andmagnetorestrictive materials. Therefore, as described for the presentinvention, P(VDF-TrFE) may be nearly ideal actuator material, includingintrinsic sensing capabilities, for haptic devices.

EAP materials are often derivatives of existing polymers and thereforeshare common processing steps with these existing products. Thiscommonality makes EAP materials potentially economical to produce inlarge volume and provides repeatable quality standards. For hapticdevice applications, EAP materials (particularly P(VDF-TrFE)) have manypotential advantages over conventional sensing and actuation methods.For example, the EAP materials have high energy density, rapid responsetime, customizability (shape and performance characteristics),compactness, easy controllability, low power consumption, high forceoutput and deflections/amount of motion, natural stiffness, both sensingand actuation functions, relatively low raw materials cost, andrelatively inexpensive manufacturing cost.

Configurations

EAP actuators and sensors can be configured in several different ways.Some of these configurations are described below.

Bending: A sandwich/layered “bimorph” structure can be provided whichcan generate single-axis displacements or forces in two directions. Forexample, FIG. 2 a shows a side view of an EAP structure 200. A bendingout of the flat plane of the structure 200 can be performed, as shown inFIG. 2 a. This can be accomplished with IPMC structures, or, a polymersurrounded in a sandwich structure by a gold electrode and a carbonelectrode, for example. Alternatively, as shown in the top plan view ofFIG. 2 b, a bending within the plane of the structure 202 can beperformed, e.g. using water dragging by cation. A bending beam can alsobe used as a sensor, such as an IEM-Pt composite sensor placed betweentwo electrodes.

Linear motion: FIG. 2 c shows a side view of a multiple layer bendingbeam 204 which is capable of both bending as well as longitudinal(lengthwise) displacements and forces. The beam 204 can include a topelectrode 206 a, a bottom electrode 206 b, a middle electrode 206 c,which can be made of a standard conductive material. Two elastomerlayers 208 are positioned between the electrodes. A linear motion of thebeam 204, as shown by arrow 209, is created by actuating both the topelectrode and the bottom electrode. A bending motion can be created byactuating either the top electrode or the bottom electrode (the middleelectrode is coupled to ground). Other embodiments may provide onlylinear, axial deflection and no bending by using a sandwich structure.

Multiple degrees of freedom: FIG. 2 d is a perspective view of acylinder 210 that may deflect in two degrees of freedom (fourdirections) using combined signals applied to four electrodes. Fourelectrodes 211 are shown in this example, which are positioned on anelastomer cylindrical layer 207. In other embodiments, otherthree-dimensional structures of electrodes can be provided to deflect intwo degrees of freedom (four directions) or additional degrees offreedom. For example, a structure having a triangular or other polygonalcross-section can be provided.

Area expansion: FIG. 2 e shows a structure including a soft dielectric212 squeezed between two compliant electrodes 213. The dielectric 212expands in area, e.g., along one or more linear directions, as shown byarrows 214. In other embodiments, the dielectric can expand radially (ina circular dielectric), e.g. a polymer film stretched on a rigid framebetween two electrodes. Other shaped dielectrics may also be used. Thethickness of the dielectric compresses simultaneously, as shown byarrows 215.

Axial motion: FIG. 2 f illustrates a sandwich structure of two polymerlayers that are rolled into a cylinder 216, where electrical andmechanical connections can be made at regions 218 and the active,expanding region 220 is positioned between and includes overlappingelectrodes. The resulting axial motion is indicated by arrow 219. Inother embodiments, a sandwich structure can be rolled into a coil toproduce rotational movement (a torque).

Diaphragm: Thin diaphragms can use planar expansion to generate in-planeor out-of-plane deflections, closing of apertures, etc.

Haptic Device Embodiments

The major classes of use contemplated for EAP actuators and sensors inhaptic devices are inertial vibration actuators, linear actuators,rotational actuators, brakes, and miscellaneous uses. Many of theseclasses are described below in the provided example embodiments ofhaptic devices of the present invention.

It should be noted that the EAP actuators described in the belowembodiments can be controlled by a local microprocessor in accordancewith firmware and/or host computer commands or signals, or a hostcomputer can directly control the actuator(s).

FIG. 3 is an illustration of one example of an interface device 12 thatcan be used with the present invention. Mouse device 250 is a devicehaving a housing 252 that is moved by the user in two planar degrees offreedom (x- and y-axes) to provide control signals to a host computer,e.g. to control the position of a cursor in a displayed graphicalenvironment. As is well known to those of skill in the art, mouse device250 includes one or more sensors to detect its x- and y position, suchas a ball and roller sensor assembly, an optical sensor, or other typesof sensor. A scroll wheel 254 can be provided to allow the user toprovide additional input by rotating the wheel. Mouse buttons 256 can bepressed by the user to provide input signals to the host computer.

Three general types of haptic feedback are described in relation to themouse embodiment 250; other types are also possible, and all may beimplemented with other types of haptic feedback devices (joysticks,trackballs, steering wheels, laptop sensor pads, etc.). The threegeneral types are button haptic feedback, inertial haptic feedback, andhousing motion haptic feedback.

FIGS. 3 a-3 c illustrate generally the output of haptic feedback on abutton. Button haptic feedback can be provided in several differentways. In FIG. 3 a, the EAP actuator is used to provide haptic feedbackand actuate motion of a button 256 in the button degree of freedom asshown by the arrow, i.e., in the direction of clicking or moving thebutton, where the button can be moved to another position as indicatedby the dashed lines. The EAP structure (not shown) can, for example, bedirectly coupled to the button or be coupled to the button via atransmission or intermediate member (spring, flexure, etc.) For example,a linearly-extending EAP actuator can push or pull the button in itsdegree of freedom.

In the top plan view of FIG. 3 b, an EAP actuator provides hapticfeedback to button 256 a in the direction of lateral button motion,i.e., motion in a direction substantially perpendicular to button motionand, in the case of a mouse embodiment, substantially parallel to mousemotion in its degree of freedom. The EAP actuator can be coupled to thebutton directly or through an intermediate structure. For example, alinearly-moving EAP actuator can push or pull the button from the sideof the button 256 a. Furthermore, the button can be moved along thex-axis or the y-axis, or along both axes, e.g. using two EAP actuators.A haptic button can also be implemented as button 256 b, which is astandard button that may be clicked or pressed to provide an inputsignal, and which also includes a patch 258 provided on the button. Thepatch can be a separate film or member that can be moved by an EAPactuator independently of the surrounding portions of the button 256 b.For example, as shown, the patch 258 can be positioned near the centerof the button 256 b; alternatively, the patch can be positioned on oneside or edge of the button 256 b.

FIG. 3 c is a top plan view of another button embodiment, where atactile array 260 of haptic EAP elements 262 can be placed on or a neara button 256. Each EAP element 262 of the array can be individuallymoved up or down on the z-axis, allowing a variety of sensations to beconveyed to the user who is contacting the array or part of the arraywhile resting a finger on the button. In other embodiments, a 1D array(single line of elements) can be provided instead of the 2-D arrayshown. EAP tactile arrays are described in greater detail below.

Another general type of haptic feedback is inertial feedback, whichinvolves moving a mass with respect to an inertial ground such that theoscillations are conveyed to the user as vibrations or pulses. Inertialhaptic feedback can be provided using EAP actuators of the presentinvention. FIG. 4 a shows a linear shaker 270 using an EAP actuator,where a mass M is moved linearly by the EAP structure 272 that can moveaxially, as indicated by arrow 274. An oscillating control waveform 274is input to the shaker to cause the EAP actuator to oscillate back andforth. This causes an inertial force on the housing of the device towhich the EAP actuator is attached. Such feedback can be provided for amouse, gamepad, joystick handle or base, trigger button on any device, astylus, a tablet, a glove, a knob, a remote control, or other handhelddevice or structure on a device.

FIG. 4 b illustrates a rotary inertial EAP actuator 280, which includesan EAP element 282 that is configured like a coil to move a mass 284 ina rotational degree of freedom and thus provide rotary inertial forcesto a housing or structure to which the actuator is coupled. The innerend 288 of the element 282 can be grounded to provide a reference forthe other end of the element which oscillates. For example, the mass 284can be oscillated approximately about the axis of rotation A, whereexamples of extreme positions are shown by the dashed lines. Thepositive and negative connections 286, as with all the embodiments shownwith such connections herein, indicate that a signal or waveform can beapplied to the EAP actuator to cause it to move.

FIG. 4 c shows a multi-axis shaker module 290 which includes threemasses M1, M2, and M3, each coupled to an associated EAP actuatorstructure 292 that is similar to the structure of FIG. 4 a. Preferably,each EAP structure is oriented along a different axis (x, y, and z) toallow a mass to be linearly moved along the associated axis. When allthree masses are moved simultaneously, inertial forces are provided inall three degrees of freedom, allowing more complex and realisticinertial haptic feedback to be output to the user of the haptic device.In other embodiments, masses and actuators are provided in only twodegrees of freedom, or can be oriented at different angles.

Housing motion haptic feedback is another general type of hapticfeedback and can also be output according to the present invention usingone or more EAP actuators. FIG. 5 a shows an up-down motion of theentire housing 302 of mouse 300 (or the entire top-sides portion of thehousing, excluding the bottom plate), as indicated by arrow 304 and thedashed lines 306. An EAP actuator 308 can be coupled directly to themoveable housing, as shown, and moved linearly. Or the EAP element canbe coupled to the housing via a hinge, flexure, or other structure. Inother embodiments, the EAP actuator can be made to bend to cause theup-down motion.

FIG. 5 b illustrates a mouse 320 including one or more moveable sections322 provided in or on the side housing 324 of the mouse, where an EAPactuator can be coupled to each moveable section to move it. Forexample, a flexible material or hinge, such as rubber or flexibleplastic, can couple the moveable sections 322 to the rest of the housing324 to allow the motion. EAP actuators that bend, move linearly, orexpand in area can be used to move the sections 322.

In FIG. 5 c, a mouse 330 includes portions 332 of the housing 324 whichare moveable in a split shell configuration, allowing a dedicated EAPactuator coupled to each portion 322 to drive its associated portionindependently of the other portion 322. The user's palm which contactsthe moving portions 322 will feel the tactile sensations as the portionsare moved, such as vibrations and the like. Alternatively, the portions322 can be driven simultaneously or with a single EAP actuator havinglinkages to both sections.

FIG. 5 d shows a mouse 340 including an upper portion 342 of the housingmoveable with respect to the remaining housing portion 344 as shown byarrow 346 and driven by an EAP actuator, where the user's palm contactsthe moveable portion to feel the haptic contact forces. A hinge or otherflexure can couple the moveable portion 342 with the base portion 344.Differently-sized portions 342 can be provided in other embodiments.

Ball haptic feedback provides haptic forces acting on a ball, such as atrackball device, a ball used in a sensor mechanism in a mouse device,or other frictional movement device, to output haptic feedback in thedegrees of freedom of motion of the interface device. For example, asshown in FIG. 6, a ball actuation assembly 350 includes a sphere or ball352, an X roller 354, A Y roller 356, an X sensor 358, a Y sensor 360,an X EAP brake 362, a Y EAP brake 364, and a support 366 supporting thebrakes. The ball 352 rolls against the cylindrical rollers 354 and 365(the ball can be biased against the rollers by using, for example, athird roller that is spring biased against the ball). The encodersensors 358 and 360 sense the position of the rollers, and thus theball, in the x and y axes by providing an encoder wheel attached to aroller and an emitter-detector to detect slots or marks in the wheel, asis well known. The EAP brakes 362 and 364 each include a brake shoe 368(which can be of any suitable material) on their ends facing the rollers354 or 356. The EAP brakes are provided with a control electrical signalto induce linear motion in the EAP elements and thus on brake shoes 368to cause the brake shoes to frictionally contact the rolling members 354and/or 356. This frictional contact causes resistance to motion of theball 352, which the user feels as resistance to motion and hapticfeedback. The EAP brakes 362 and 364 can be moved different distances tocause different amounts of friction on the rollers, thus causingdifferent amounts of friction on the ball. This resistance also causesresistance to the mouse in its degrees of freedom, in such embodiments.

Some embodiments of the interface device 12 can include a wheel, such asmouse wheel 254 shown in FIG. 3. The wheel can be rotated by the user'sfinger(s) to provide position signals to a computer indicating aposition or motion of the wheel, and which can be used to scrolldocuments displayed by a host computer, move a cursor and select an itemin a list, or perform other functions well known to those of skill inthe art. Haptic feedback can be output in the rotational degree offreedom of the wheel, and/or on the wheel itself, using an EAP actuator.For example, FIG. 7 a illustrates a wheel 380 which includes an EAProtary inertial shaker 382. The shaker includes a curved EAP element 384and a mass 386 positioned at the end of the element 384. The mass 386can be oscillating using a periodic waveform as an input signal, similarto the shaker shown in FIG. 4 b. This causes inertial sensation on thewheel 380, which are transferred to the user's finger 388.

In FIG. 7 b, a wheel 400 includes number of radially expanding EAPactuators 402. Each actuator 402, as shown in FIG. 7 c, can be similarto the area expansion actuator shown in FIG. 2 e above to provide anexpanding outer surface to the wheel 400. Multiple EAP actuators areprovided around the circumference of the wheel, where the expansion ofeach actuator can be controlled individually to provide tactilesensations to the user's finger based on the collective movement ofthose actuators in contact with the user's finger. Other types of EAPactuators, such as linear moving elements, can alternatively be used.

In FIG. 7 d, an EAP brake device 410 is shown which includes an EAPbrake 412 that includes an EAP linearly-moving structure 414 coupled toa brake shoe 416. The brake shoe 416 frictionally contacts a rotatingaxle 418 of the wheel 420, similar to the EAP brake of FIG. 6, to causeresistance in the rotational degree of freedom of the wheel.

FIG. 7 e illustrates a wheel device 430 that uses an EAP actuator toprovide lateral motion or forces on the wheel, parallel to the axis ofrotation of the wheel. A linearly-moving EAP actuator 432 can be coupledto the rotating axle 434 (or to a member rotatably coupled to the axle)to provide horizontal forces and motion, as indicated by arrow 436, towheel 438. Also, in some embodiments, a linearly-moving EAP actuator 440can be coupled to a member as shown to provide a vertical force ormotion on the entire wheel device 430 as indicated by arrow 442. Theseembodiments can also be used with a rotary control knob used in avariety of devices.

Other interface devices 12 can be provided with haptic feedback usingEAP actuators. For example, in FIG. 8 a, a “trackpoint” controller 450is shown, which is often positioned between keys on a standard computerkeyboard of a laptop or other computer and used to control a cursor orother pointing function by being moved in normal displacementdirections, as shown by arrows 452. For example, the trackpoint can betranslated or rotationally moved in the two degrees of freedom. Thetrackpoint 450 can be provided with an EAP actuator 454, which can becontrolled to move linearly vertically (z-axis) in both directions toprovide z-axis tactile feedback to the user's finger operating thetrackpoint. In some embodiments, the EAP actuator 454 can also oralternatively act as a sensor to detect when the user is contacting thetrackpoint and/or the amount of z-axis pressure or displacement exertedby the user on the trackpoint. The amount z-axis pressure can be used tocontrol a value or parameter in an application program, such as a ratecontrol function (scrolling, panning, zooming, velocity of a virtualvehicle in a game, etc.) or the position of a cursor in a representationof a third dimension. The trackpoint controller can be considered theinterface device as well as a manipulandum of the interface device.

In FIG. 8 b, a trackpoint controller 460 can include a linearly-movingEAP actuator similar to that of FIG. 8 a but positioned within a hollowinterior of a vertical post 462. The cap 461 of the trackpoint can betextured to allow a stronger user grip and includes an aperture 465. Asshown in FIG. 8 c, the EAP actuator 464 can be controlled to extend apoker 466 or other member that is coupled to the EAP actuator 464through the aperture into the skin of the user's finger contacting thetop of the trackpoint controller 460. The poker can be withdrawn andextended to provide texture sensations to the user.

FIG. 8 d shows another embodiment of a trackpoint controller 470, whereEAP actuators are used to provide haptic feedback in the normal x-ydirections of control of the trackpoint controller. Four linearly-movingEAP actuators 472 are placed at 90 degree increments around a base 474of the controller to provide linear force and/or motion to the centralvertical post 476. The post can be moved linearly by the user in the x-and/or y-directions to control a cursor, value, etc. It should be notedthat the embodiments shown in FIGS. 8 a-8 d can be used with standard,larger-sized joysticks as well as trackpoint controllers, or other typesof interface devices.

Tactile arrays are multiple vertical “pins” that form a plane of contactperpendicular to the orientation of the pins at the pin's contactsurfaces. The contact surfaces of the pins are contacted by a user'sfingers or palm. Each pin can be individually moved perpendicularly tothe pin's lengthwise axis, such that collectively the pins can be movedto convey different tactile sensations to the user. FIG. 9 a shows asingle “pin” 490, which is implemented as an EAP actuator 494 that canbe linearly moved as indicated by arrow 496. A tactile cap 492 ispositioned on the EAP pin 494 to be contacted by a user. In FIG. 9 b, aplurality of the pins 490 of FIG. 9 a have been positioned in a matrixto form a tactile array 500, where each pin 490 can be individuallycontrolled to move vertically in either direction. An adjacent surface502 provides a reference surface for the user's fingers. In FIG. 9 c, ahigh density array 504 of EAP pins 490 is shown, where each EAP pin canrepresent a pixel-sized element. This array of pins can be used toindicate haptically to the user when certain features in a graphicalenvironment are crossed or interacted with. For example, the array canbe provided as a trackpad, where the position of the user's finger onthe array determines the position of a cursor or entity in a graphicalenvironment. The array of pins can be matrix scanned (or individuallyaddressed) to sense where the user's finger current is on the array.When the user's finger moves over a border of a window, the EAP pinscorresponding to the border location are moved upwards, giving theuser's finger the sensation of crossing over a 3-D border. Otherdisplayed features such as icons, folders, etc. can also be similarlyhaptically indicated. The high density array 504 can also be used toprovide other tactile sensations based on interactions or eventsimplemented in a computer environment.

FIG. 9 d shows another embodiment 510 using the EAP pins describedabove. A lateral motion tactile element/array can be provided, wheretactile sensations are provided moving pins perpendicular to theirlengthwise axes (laterally). Each pin is moved laterally to providestretching of the user's skin or shear sensations instead of indentingthe skin of the user as in the embodiments of FIGS. 9 a-9 c. More spacecan be provided between the pins to allow for the lateral motion. Whenusing EAP actuators, one way to provide such lateral motion is to placetwo linearly-moving EAP actuators 512 on a grounded element, and place aflexible membrane 514 (or other member) over the actuators 512, where alateral moving element 516 is placed on the flexible membrane 514 asshown in FIG. 9 d. One or both of the EAP actuators 512 is movedvertically (if both are moved, it is in opposite directions), causingthe flexible membrane to flex and the lateral element 516 to rock leftor right as indicated by arrow 518. Alternatively, as shown in FIG. 9 e,an EAP structure 520 that can be directly moved laterally using acontrol signal, such as referred to above in FIG. 2 b and/or an elementhaving sandwiched layers, can be used to provide the desired lateralmotion. The actuator 520 can be moved laterally in one degree offreedom, or in some embodiments can be moved in two.

EAP actuators can be used to provide specific forces in particularapplications. For example, FIG. 10 is a side elevation view of an EAPbrake 530 used in a medical device, where a catheter wire 532 (orlaparoscopic extension, needle, or other portion of medical or otherinstrument) is used in a haptic feedback medical simulation thatprovides forces on the medical instrument to simulate a medicalprocedure. An EAP brake includes an EAP element 534 that is coupled to abrake shoe 536 that can be moved laterally against the catheter wire532, causing friction in the linear degree of freedom of the wire. Theamount of friction can be adjusted by moving the EAP brake differentdistances. Another EAP brake can be used to provide resistance in therotary degree of freedom of the wire 532.

Trigger devices can also make use of EAP actuators. FIG. 11 is a sideelevational view of a device 540 including a trigger 542 that is pressedby a user to provide a signal to a game, simulation, or other program ordevice. The trigger 542 can be included in an interface device such as agamepad, joystick, mouse, etc. For example, the trigger 542 can rotateabout an axis of rotation B, which can be a coupling to a housing of theinterface device. An EAP actuator 544 can be positioned between thetrigger and a grounded switch 546. The switch 546 sends a signalindicating activation when a portion 548 is pressed. A spring 550normally biases a contact plate 552 away from the switch 546; when theplate 552 is moved by the EAP actuator 544, the spring is compressed andthe plate hits the portion 548 of the switch 546, activating it. Thespring 550, meanwhile, biases the trigger back to its origin or restposition as well as providing a spring resistance force to triggermotion. The EAP actuator can be used to move in opposition to, or inconjunction with, trigger motion to provide a haptic sensation to theuser pushing the trigger (this EAP force can supplement or override thespring force from 550). The actuator can thus make it easier or moredifficult for the trigger to cause the switch to change states. Forexample, different resistances, damping, pulses, or vibrations can beoutput, as in all the linear EAP actuator embodiments described herein.

FIG. 12 a shows a rotary knob 560 that can be used to control functionsin a wide variety of devices. A spiral or coil EAP actuator 562 can bepositioned inside the knob so that the EAP actuator exerts a torque onthe knob when it is activated. Resistance or force can thus be providedin the rotary degree of freedom of the knob, as indicated by arrow 564,although a knob of limited rotational range should be used.

FIG. 12 b illustrates a knob device 570 that includes an EAP actuator.Knob 572 is coupled to a rotating shaft 574, which is coupled to acylindrical brake member 576 that can include a frictional surface. EAPactuator 578 includes a brake shoe 580 that is moved by the actuator 578to contact the brake member 576. This engagement provides frictionalforces on the shaft 574 and knob 572. This embodiment allows a knobhaving an unlimited (continuous) rotational range to be used. A linearEAP element can be used, as described in braking embodiments above.

FIG. 13 is a side elevational view of a braking embodiment 590 for arotating disk. Disk 592 rotated about axis C. A caliper 594 ispositioned at one end of the disk, and an EAP actuator 596 is coupled toone end of the caliper. The EAP actuator can be moved linearly to move abrake shoe 598 against the spinning cross-sectional surface of the disk,thus causing frictional resistance to the disk. A brake shoe 600 can bepositioned on the other end of the caliper 594, opposite the brake shoe598. The disk can be coupled to a variety of objects, such as a joystickhandle or mouse, a rotating finger wheel or knob, or a rotating axle ina vehicle.

A stylus-shaped interface device can also be provided with an EAPactuator to produce haptic feedback to the user of the stylus. A styluscan be used to point to or select objects on a screen, or draw or writelines by contacting the stylus with a tablet or with a display screensurface, e.g. on Personal Digital Assistants (PDA's), touch screens,graphics tablets, laptop computers, etc. For example, FIG. 14 a shows astylus 610 having a moveable tip 612, where the tip is moved by an EAPactuator 614 that is coupled to the tip and positioned inside the stylushousing. The EAP actuator moves linearly and causes the tip member 616to move linearly through an aperture in the stylus housing. The EAPactuator can be controlled to produce vibrations, pulses, or other forcesensations on the tip and thus to the user holding the stylus.

FIG. 14 b shows a different embodiment 620 that causes a front endportion 622 of the stylus to linearly move with respect to the backportion 624 of the stylus. A rubber bellows 626 can be positionedbetween the moving front portion and the back portion, and an EAPactuator (not shown) can be positioned inside the stylus housing. TheEAP actuator can be a linearly-moving element that is coupled to thefront end portion 622 to move that portion similarly to moving the tipmember as shown in FIG. 14 a. Haptic sensations can be output to theuser similarly as described with respect to FIG. 14 a.

Other features of a stylus can also be actuated using EAP actuators. InFIG. 14 c, a stylus 640 is shown having a button 642 which can becontrolled (by a host computer or other controller) to linearly moveback and forth by coupling a linearly moving EAP actuator 644 to thebutton as shown. The button can be actuated to correspond tointeractions between a controlled cursor and other displayed objects,for example.

In FIG. 14 d, a stylus 650 includes an expanding grip 652 which can beimplemented using EAP actuators. The cylindrical grip provides anexpanding circumference that is haptically discernible to the usergripping the cylindrical grip. The grip can be expanded and contractedto provide various haptic sensations, such as pulses, vibrations, 3-Dsurface simulations, etc. The grip can be implemented using a pluralityof EAP actuators 654 (four are shown) that are disc-shaped and whichexpand in circumference with the activation signal is applied, asindicated in FIG. 14 e which shows a single EAP actuator 654. Theseactuators can be similar to the EAP structure described above withrespect to FIG. 2 e.

Other devices can also be used with EAP actuators. For example, as shownin FIG. 15 a, a steering wheel 660 of a steering wheel controller devicecan be provided with an EAP inertial shaker 662 coupled in or on thewheel to provide inertial forces to the user contacting the steeringwheel and which are coordinated with displayed events or interactions.The inertial shaker can be similar to the shaker described above withreference to FIG. 4 a. Brakes can also be provided to exert frictionalforces in the degree of freedom of the steering wheel, similar to theknob of FIG. 12 b. FIG. 15 b shows a joystick handle 666 of a joystickcontroller, where the handle is similarly outfitted with an inertial EAPactuator 668 provided within the joystick handle to output inertialforces on the joystick handle.

FIG. 15 c is a perspective view of a joystick embodiment 680 thatprovides passive force feedback to the joystick. Joystick handle 682 isplaced in apertures of two rotating members 684 a and 684 b. When thehandle 682 is rotated in a direction, the corresponding member 684rotates as well. Frictional brake disks 686 a and 686 b are coupled totheir associated rotating members 684 a and 684 b. EAP brakes 688 a and688 b provide frictional forces on the disks 686 which causes resistancein the two degrees of freedom of the joystick handle (sensors, notshown, sense the rotational motion of the joystick handle). For example,the EAP brakes can include linearly-moving elements, similar to otherbrake embodiments described herein. FIG. 15 d illustrates one example ofan EAP brake caliper that can be used as an EAP brake 688, where alinearly-moving EAP actuator 690 coupled to a caliper support 691 can becoupled to a brake shoe 692 that frictionally contacts the disk 686.

EAP actuators as disclosed herein can also be used on other types ofcontrollers. For example, FIG. 16 is a perspective view of a cylindricalpointer controller 700, which includes a cylinder 702 that can berotated about its lengthwise axis as indicated by arrow 704 to provideinput in one degree of freedom (e.g. move a cursor along one axis) andcan be translated parallel to its axis of rotation as indicated by arrow706 on a carriage 708 to provide input in another degree of freedom(e.g. move a cursor along the other axis). Sensors (not shown) detectthe rotation and translation. Such a controller is described in greaterdetail in U.S. Pat. No. 4,896,554, incorporated herein by reference. Inone embodiment, an EAP brake 710 can move a brake shoe against an axle712 coupled to the cylinder to provide frictional braking forces in therotational degree of freedom. That EAP brake and the cylinder can betranslated linearly on carriage 708, and another EAP brake 714 can applybraking frictional forces on the carriage in the translatory degree offreedom. Other types of EAP actuators can also be used in a cylindricalcontroller, e.g. inertial shakers.

FIG. 17 a illustrates an embodiment 720 providing skin tactors using anEAP actuator. Skin tactors are similar to the pin grid arrays describedabove, in which one or more moving elements contacts a user's skin toprovide a tactile sensation. One or more skin tactors can be provided ina haptic glove to engage the user's fingers and palm, in arrays on avest to engage the user's chest or other body parts, or in other areasthat can contact a user's skin. In FIG. 17 a, an EAP linearly-movingactuator 722 is coupled to a tactor element 724, where the tactorelement is moved linearly into the user's skin through an opening in asupport 726. The tactor element is preferably moved and/or oscillatedwith a waveform similarly to the pin grid arrays described above.

FIG. 17 b illustrates another embodiment 730 having tactor elements. Alinearly-moving EAP actuator 732 is coupled to a support 734. A tactorelement 736 is coupled to a member 738 that is coupled to the end of theactuator 732. When the actuator 732 is moved linearly, the tactorelement is moved laterally as indicated by arrow 740. This motionstretches the user's skin instead of moving an element into the skin.The grounded surface surrounding the tactor element, as well as thetactor element itself, can include ridges 742 or bumps to engage theuser's skin. The stationary ridges on the grounded surface hold anengaged portion of the user's skin in place, while the moving ridges onthe tactor element 736 stretch the middle area of the engaged portion ofuser's skin, creating a highly effective tactile sensation.

Other types of interface devices can employ EAP actuators, such astouchpads on laptop computers, PDA and game device screens used withstyluses or fingers, etc., where haptic sensations are output directlyon the touchpad or screen. For example, the touchscreens and touchpadsdisclosed in copending application Ser. No. 09/487,737, incorporatedherein by reference in its entirety, can be coupled to bending, inertialshaker, or linearly-moving EAP actuators as disclosed herein ratherthan, for example, piezoelectric actuators. Tactile computer keyboardsand keypads (as disclosed in copending application Ser. No. 09/570,361,incorporated herein by reference in its entirety), direction pads ongamepads (as disclosed in copending application Ser. No. 09/467,309,incorporated herein by reference in its entirety), and other interfacedevices may be used with the EAP actuators according to the presentinvention.

While this invention has been described in terms of several preferredembodiments, it is contemplated that alterations, permutations andequivalents thereof will become apparent to those skilled in the artupon a reading of the specification and study of the drawings. Forexample, many different types of haptic sensations can be provided withthe actuators of the present invention. Furthermore, certain terminologyhas been used for the purposes of descriptive clarity, and not to limitthe present invention.

1. A device comprising; a housing having a touch surface adapted to betouched by a user; a sensor coupled to the touch surface and configuredto detect at least one of a position or movement of the user's touch onat least a portion of the touch surface, the sensor configured to outputsensor signals associated with the position or movement; and anelectroactive polymer actuator coupled to the housing and configured tooutput a haptic feedback force upon receiving an control signal from aprocessor, the control signal being associated with the output sensorsignals.
 2. The device of claim 1, wherein the touch surface is orientedalong a plane, the electroactive polymer actuator outputting the hapticfeedback force in a direction substantially perpendicular to the plane.3. The device of claim 1 wherein the electroactive polymer physicallymoves in the direction substantially perpendicular to the plane uponreceiving the control signal.
 4. The device of claim 1, wherein theelectroactive polymer further comprises a plurality of electroactivepolymer actuator pins, each pin physically moveable in the directionsubstantially perpendicular to the plane upon receiving the controlsignal.
 5. The device of claim 4, further comprising a flexible membranecoupled to an end of two adjacent electroactive polymer actuators inplurality, wherein movement of at least one of the actuators impartsforce on the membrane.
 6. The device of claim 1, wherein the processoris of a computer system running a program displaying a graphical userinterface, wherein at least a portion of the graphical user interface isconfigured to cause the processor to output the control signal upon thesensor output signals indicating the position or movement at adesignated haptic location on the graphical user interface.
 7. Thedevice of claim 1, wherein the touch surface is a touch screenconfigured to receive inputs from the user to a graphical user interfacevia the touch surface.
 8. A method comprising; selecting a housinghaving a touch surface adapted to be touched by a user; sensing at leastone of a position or movement of the user's touch on at least a portionof the touch surface using a sensor, the sensor configured to an outputsensor signal associated with the position or movement to a processor;and outputting a haptic feedback force using an electroactive polymeractuator upon receiving an control signal from a processor, wherein thecontrol signal is associated with the output sensor signal.
 9. Themethod of claim 8, wherein the outputting further comprises outputtingthe haptic feedback force in a direction substantially perpendicular toa plane of the touch surface.
 10. The method of claim 9, wherein theelectroactive polymer physically moves in the direction substantiallyperpendicular to the plane upon receiving the control signal.
 11. Themethod of claim 8, wherein the electroactive polymer further comprises aplurality of electroactive polymer actuator pins, each pin physicallymoveable in the direction substantially perpendicular to the plane uponreceiving the control signal.
 12. The method of claim 11, furthercomprising a flexible membrane coupled to an end of two adjacentelectroactive polymer actuators in plurality, wherein movement of atleast one of the actuators imparts force on the membrane.
 13. The methodof claim 8, further comprising running a program displaying a graphicaluser interface, wherein at least a portion of the graphical userinterface is configured to cause the processor to output the controlsignal upon the sensor output signals indicating the position ormovement at a designated haptic location on the graphical userinterface.
 14. The method of claim 8, wherein the touch surface is atouch screen configured to receive inputs from the user to a graphicaluser interface via the touch surface.
 15. Logic encoded in one or moretangible media for execution and when executed operable to perform amethod, the method comprising: receiving a sensor signal associated witha sensed position or movement of a user's touch on a touch surfacehaving a sensor coupled thereto, wherein the sensor outputs the sensorsignal; and outputting a control signal to an electroactive polymeractuator upon the sensor signal indicating the sensed position ormovement of the user's touch is at a designated haptic feedback forcelocation, wherein the electroactive polymer actuator output a hapticfeedback force to the touch surface upon receiving the control signalfrom a processor.
 16. The method of claim 15, wherein the control signalcauses the electroactive polymer actuator to output the haptic feedbackforce in a direction substantially perpendicular to a plane of the touchsurface.
 17. The method of claim 16, wherein the electroactive polymerphysically moves in the direction substantially perpendicular to theplane upon receiving the control signal.
 18. The method of claim 15,wherein the electroactive polymer further comprises a plurality ofelectroactive polymer actuator pins, each pin physically moveable in thedirection substantially perpendicular to the plane upon receiving thecontrol signal.
 19. The method of claim 18, further comprising aflexible membrane coupled to an end of two adjacent electroactivepolymer actuators in plurality, wherein movement of at least one of theactuators imparts force on the membrane.
 20. The method of claim 15,further comprising running a software program displaying a graphicaluser interface, wherein at least a portion of the graphical userinterface is configured to cause the outputting of the control signalupon the sensor output signals indicating the position or movement atthe designated haptic location on the graphical user interface.